Fracturing methods commonly involve a technique of starting at the well bottom or isolating a portion of the well that is not to be perforated and fractured with a plug. The first zone is then perforated and fractured and then another plug is placed above the recently perforated zone and the process is repeated in a bottom up direction until all the zones are perforated and fractured. At the end of that process the collection of barriers are milled out. To aid the milling process the plugs can be made of non-metallic or composite materials. While this technique is workable, there was still a lot of time spent to mill out even the softer bridge plugs and remove that milling debris from the wellbore.
In the past there have been plugs used that are milled out as described in U.S. Pat. No. 7,533,721. Some are forcibly broken to open a passage such as in U.S. Pat. No. 6,026,903. Other designs created a plug with material that responded to a magnetic field as the field was applied and removed when the field was removed. This design was described in U.S. Pat. Nos. 6,926,089 and 6,568,470. In a multi-lateral application a plug was dissolved from within the whipstock to reopen the main bore after the lateral was completed. This is described in U.S. Pat. No. 6,145,593. Barriers that assist in extending telescoping passages and then are removed for access to fracture the formation are described in U.S. Pat. No. 5,425,424. Longitudinally extending radially expanded packers to get them to release is shown in U.S. Pat. No. 7,661,470.
What is needed and provided by the present invention is a fracturing system where thin sleeves with external seals, slips or anchors and a ball seat are run in and set in sequence. The next zone is perforated and a ball is landed on a seat and the just perforated zone is fractured. The process repeats until all the zones are fractured at which time the balls are removed from the seats preferably by dissolving them. The thin sleeves remain but are sufficiently thin to avoid materially impeding the subsequent production flow. The sleeves can be run in with coiled tubing or wireline and expanded into sealing contact using known setting tools that can, for example, push a swage through a sleeve to expand the sleeve and the external seal that can be used with the sleeve. Those skilled in the art will better appreciate the various aspects of the invention from a review of the description of the preferred embodiment and the associated FIGS. while appreciating that the full scope of the invention is to be found in the appended claims.